#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
int main()
{
	int n = 0, sum = 0,  arr[10] = { 0 };
	for (n = 0;n < 10;n++)
	{
		scanf("%d", &arr[n]);
		sum = sum + arr[n];
	}
	double adv = sum / 10.0;
	printf("%.2f\n", adv);
	return 0;
}